Modified Atmosphere Packaging (MAP) has taken root in the food industry and keeps gaining importance. Whereas, for a long time the actual packaging process was the centre of attention of process enhancement, conclusive leak testing increasingly becomes more important.

Protective gas packaging appeals to producers wrestling for consumers, due to its promise of fresh, attractive and high-quality goods without additional preservatives at any time and any place. However, this modern packaging technique makes comparatively high demands on the packaging process.

Most notably, the sealing process contains various sources of error that can lead to leaks: defective temperature or pressure distribution, improper sealing tool arrangement, impure or worn out tools as well as seal contaminations. Let alone defective material that can lead to undetected serial leaks. Even with special diligence during the process design, inaccurately packed goods can hardly be avoided by 100%.

Leaking Packages Become More Expensive

Meanwhile, the impact of leaking Modified Atmosphere Packaging on the product can be grave: from loss of nutrients to loss of flavour, taste, texture or colour to the point of deterioration due to pathogenic microorganisms. Depending on the product, even health risks cannot be eliminated.

In the end, there may possibly be legal consequences. Be it under private law e.g., due to positive violation of a contractual duty or subject to public law in line with the food law. Nevertheless, in many cases expensive and image damaging product recalls might be more significant for they can potentially jeopardise a company's existence.

Admittedly, leak testing in general is currently not regarded as a critical control point for the purpose of a HACCP concept: but, given the risk mentioned before it is not surprising that this topic has gained in importance for food producers.

Not least because major grocers put increasing emphasis on proven quality control of producers. Only complete leak testing of packages in the final inspection offers genuine safety. In practice, however, the intent of optimal quality in the past often collided with the aim of a preferably high output.

The reason: the available technical solutions for an in-line control simply couldn't manage the high speed of the upstream packing machines. Therefore, many businesses currently often work with sample testing.

It is Possible: Optimal Quality at High Output

All the while, there already are systems that have solved this dilemma for many food producers, for example the in-line system Leak-Master Mapmax by Witt-Gasetechnik. The MAP specialists from Witten focus on the analysis of CO₂ as a trace gas. The system features even the smallest detection of leaks. This is enabled by a measurement method developed by Witt, which evaluates the signals of a CO₂ sensor. With a speed of up to 15 cycles per minute products are conveyed into the test chamber directly after the packing process. This chamber is subjected to a certain level of vacuum briefly and this vacuum causes CO₂ to escape from the leaky package, which is then detected by a highly sensitive sensor. The measuring range lies between 0 and 5,000 ppm (parts per million) with a resolution of 1 ppm. If a product has been detected as leaky, the system can directly trigger a pusher to sort out a faulty package. Since testing of boxes and complete shipping cases is also possible, insufficient speed is usually not an obstacle anymore. Moreover, the use of CO₂ makes this solution considerably less expensive for customers than for instance testing with helium.

The system has already proven successful in numerous trans-European installations and is used for quality control of, e.g., sausage and meat products, dairy products, bread or fish.The implementation of such a 100% leak testing method should meet the legal requirements for due diligence as expected and eliminate further liability risks to a great extent. In any case it provides an efficient protection against reclamation of goods as well as possible product recalls and the involved consequences.

(Article courtesy: WITT-Gasetechnik GmbH & Co KG, Germany. The company is represented in India for this product range by Healthtech Medical Devices Pvt Ltd, Kolkata. Contact: Mr Shantanu Basu. Tel: 033-24012803. Telefax: 91-33-24012803. Mobile: 098302-58959. Email: sbasu@healthtechmedicaldevices.com)